packaging multiple javascript files - javascript

I am developing a javascript library made up of a few tightly coupled classes. The classes are broken up into individual .js files, but for brevity's sake, I envision the end user including a single .js file encompassing the entire implementation.
My question is, what is the ideal method for distributing the API? Should I simply repackage all the code into a single .js file, should I keep the existing file structure and setup a series of
document.write('<script src="file1.js"><\/script>');
commands into a 'primary' script file, or is there another way that makes more sense?
Thanks!

I think if you don't intend for the user to jump in there and need to modify it and it's tightly coupled like you mentioned you should put it all in a single JS file and then minify it.
You can provide an unminified version as well but seems for their simplicity you should put it all in a single JS file.

For performance and maintenance reasons, I believe it's better to package them into a single file. The fewer http requests made to retrieve scripts, the better performance (in general - very long scripts can also cause performance slowdown.) I'd also recommend namespacing your api.

Related

jquery structure - one function per file

I am primarily a c# programmer. I have recently been getting into some jquery development. when I am working on applications in c#, I create a new class file (.cs) for every new class that I create.
How do people generally structure their jquery/javascript applications. I would like to reuse some functionality across pages, so do I put each function in it's own .js file? or is it best practice to group like functions into files? I can't see putting each on in it's own file as that would create many calls to import individual file into a page....
How are other people handling these types of situations.
Thanks for any thoughts.
EDIT - I should have mentioned that I am beginning to look at unit testing with QUnit and figured it would be good to have proper structure of my project to better facilitate unit testing.
If you DO put them all in separate files, you would want to have a build script that combines and minimizes them into a single one (or just a few) so you do not have 500 Javascript files to download to your browser.
I would suggest putting your common functionalities to a util.js file and then arrange your javascript codes according to functionality.
However it is not a good practice to have lots of js files included in every page, thus you might consider combinin the files into a single file and minifying that final js file. this way you would have optimized your final product while being able to unit test functionalities separately.
I generally keep all plugins into their perspective files but functions I create I tend to place into a "global.js" file that the entire site will pull from. Then I don't have to worry about pulling in specific files when a need a specific function. It will all be in the global.
Put it all in one file. Multiple HTTP requests are more expensive than big files, plus you're assured that the file containing the function you need is already loaded.

Combining and Compressing multiple JavaScript files into a single file in a Django project

What is the simplest way to combine JavaScript files into a single file in a Django project?
Explanation
I want this to work with Ember.js/Backbone where you (usually) have many different JavaScript in multiple directories. Directories would all be in one folder called app/ for example, like: app/views/ app/models/ /app/routers/
Requirements
Work together with the staticfiles app
Still be separated while in development mode for easier debugging (only compile when calling collectstatic?)
Work with Require.js (guess that shouldn't be too hard, but putting it in here to be sure)
Extra credit
Explain a best practices way of combining Django and Ember/Backbone.
I am an happy user of django compressor, it does combine, minify, debug-friendly, you can use it with staticfiles, easy to plug with custom storage backend (eg. S3)
https://github.com/jezdez/django_compressor
The reason you want to combine many files into one is so to minimize latency of setting up and tearing down http requests, the fewer you make the better. However, many newer browsers are downloading JavaScript files in parallel (still executing sequentially). The consequence is that downloading a single 1Mb file may be slower than three 350Kb files.
you can use from CDNs.
As mentioned in the previous answer, django-compressor is nice, but you often get better loading times when using a dedicated javascript loader instead. My tip is to check out Head.js for example (http://headjs.com/) (there are tons other out there as well). Often combining scripts can be contra productive when considering caching, using javascript located on CDN:s etc.
One thing to remember is that Iphone 3/4 will just cache 15/25KB of javascript, so if you have huge scripts and combine them you can run into trouble. http://www.phpied.com/iphone-caching/

How to update HTML script and link references when combining JavaScript and CSS files?

Multiple sites reference combining JavaScript and CSS files to improve web page performance, including examples of using ANT build scripts to concatenate the files prior to deployment.
I've search, and haven't found any information how to automate updating references to those files in HTML and other documents. I am looking to avoid hacking together something error prone, and want to learn from others who have automated builds in the past.
Are there automated tools in the wild to complete this task that I'm not seeing? Are there recommended processes to update the script and link tags in HTML? Can these solutions be integrated with ANT or similar build tools?
There sure is and it's a smart thing to do.
I found a PHP solution, don't know it that's okay for you, but if it isn't you can still read it's source (it's not difficult) and learn a lot. The solution works like this:
Rewrite your requests like this: from css/main.css and css/skin.css to css/main.css,skin.css (of course you can put many more).
Use apache's mod_rewrite to redirect this request to a script (in our case combine.php), that will combine all files to a single one.
The script combines all the files and sends the combined file. Then it saves it to a cache folder.
Next time around it checks if there is an up-to-date version of the cache and serves that one. If the latest file modification time has changed, it discards the cache.
The solution works great and it even makes use of HTTP cache headers and spits out an [ETags], which you should do anyway.
You are correct this is a great way to speed up page loading. It will even work in conjunction with a CDN, which the other poster recommended.
Here is a small script that will pack multiple files in to one for deployment. It supports both JS and CSS, and will even "minify" them by removing whitespace, etc. Just hook this in to your build and deploy scripts.
juicer: http://cjohansen.no/en/ruby/juicer_a_css_and_javascript_packaging_tool
What even better, it will follow JS and CSS import statements, so you only need to point your HTML files to the loader file and it will work in both development and production. (Assuming you replace the loader file with the combined file on deployment.)
There are others, including some run-time solutions. But it sounds like you have a build process in place anyway.
As far as HTML updating, if you still need it, since automated deployments are very popular in the Ruby world, and you may find some standalone utilities to help even for non-ruby projects. (As above) Methinks this would be best handled by your own project's template language, though. (With a static resource revision id, or such.)
Good luck, and let us know what you find.
I think what you really want is a CDN Content Delivery Network.
Read about it here
http://developer.yahoo.com/performance/rules.html
http://en.wikipedia.org/wiki/Content_delivery_network

YUICompressor or similar in PHP?

I've been using yuicompressor.jar on my test server for on-the-fly minimisation of changed JavaScript files. Now that I have deployed the website to the public server, I noticed that the server's policies forbid the use of exec() or its equivalents, so no more java execution for me.
Is there a decent on-the-fly JS compressor implemented in PHP? The only thing resembling this that I was able to find was Minify, but it's more of a full-blown compression solution with cache and everything. I want to keep the files separate and have the minimised files follow my own naming conventions, so Minify is a bit too complex for this purpose.
The tool, like yuicompressor, should be able to take either a filename or JavaScript as input and should either write to a file or output the compressed JavaScript.
EDIT: To clarify, I'm looking for something that does not have to be used as a standalone (i.e. it can be called from a function, rather than sniffing my GET variables). If I just wanted a compressor, Minify would obviously be a good choice.
EDIT2: A lot has changed in the five years since I asked this question. Today I would strongly recommend separating the front-end workflow from the server code. There are plenty of good tools for JS development around and except for the most trivial jQuery enhancements it's a better idea to have a full workflow with automated bundling, testing and linting in place and just deploy the minified bundles rather than the raw files.
Yes there is, it's called minify.
The only thing in to worry about in the way of complexity is setting up a group, and there's really nothing to it. Edit the groupsConfig.php file if you want multiple JS/CSS in one <script> or <link> statement:
return array(
'js-common' => array('//js/jquery/jquery-1.3.2.min.js', '//js/common.js', '//js/visuals.js',
'//js/jquery/facebox.js'),
'css-common' => array('//css/main.css', '//css/layout.css','//css/facebox.css')
);
To include the above 'js-common' group, do this:
<script type="text/javascript" src="/min/g=js-common"></script>
(i know i was looking for the exact same thing not knowing how to deal directly with the jar file using php - that's how i ended up here so i'm sharing what i found)
Minify is a huge library with tons of functionalities. However the minifying part is a very tiny class : http://code.google.com/p/minify/source/browse/trunk/min/lib/Minify/YUICompressor.php
& very very easy to use :
//set the path to the jar file
Minify_YUIcompressor::$jarFile=_ROOT.'libs/java/yuicompressor.jar';
//set the path to a writable temp folder
Minify_YUIcompressor::$tempDir=_ROOT.'temp/';
//minify
$yourcssminified=Minify_YUIcompressor::minifyCss($yourcssstringnotminified,$youroptions)
same process for js, if you need more functionalities just pick from the library & read the source to see how you can make direct call from your app.
I didn't read the question well, since minify is based on using the jar files, the op can't use it anyway with his server config
Minify also include other minifying methods than yui, for example:
http://code.google.com/p/minify/source/browse/trunk/min/lib/JSMinPlus.php?r=443&spec=svn468
Try Lissa:
Lissa is a generic CSS and JavaScript loading utility. Lissa is an extension of the YUI PHP Loader aimed at solving one of the current loader limitations; combo loading. YUI PHP Loader ships with a combo loader that is capable of reducing HTTP requests and increasing performance by outputting all the YUI JavaScript and/or CSS requirements as a single request per resource type. Meaning even if you needed 8 YUI components which ultimately boil down to say 13 files you would still only make 2 HTTP requests; one for the CSS and another for the JavaScript. That's great, but what about custom non-YUI resources. YUI PHP Loader will load them, but it loads them as separate includes and thus they miss out on benefits of the combo service and the number of HTTP requests for the page increases. Lissa works around this limitation by using the YUI PHP Loader to handle the loading and sort of YUI and/or custom resource dependencies and pairs that functional with Minify.

How do you manage your Javascript files?

Nowadays, we have tons of Javascript libraries per page in addition to the Javascript files we write ourselves. How do you manage them all? How do you minify them in an organized way?
Organization
All of my scripts are maintained in a directory structure that I follow whenever I work on a site. The directory structure normally goes something like this:
+--root
|--javascript
|--lib
|--prototype.js
|--scriptaculous
|--scriptaculous.js
|--effects.js
|--..
|--myOwnScript.js
|--myOwnScript2.js
If, on the off chance, that I'm working on a team uses an inordinate amount of scripts, then I'll normally create a custom directory in which we'll organize scripts by relationship. This doesn't happen terribly often, though.
Compression
Though there are a lot of different compressors and obfuscators out there, I always come back to YUI Compressor.
Inclusion
Unless a site is using some form of a master page, CMS, or something that dictates what can be included on a page beyond my control, I only included the scripts necessarily for the given page just for the small performance sake. If a page doesn't require any script, there will be no script inclusions on that page.
First of all, YUI Compressor.
Keeping them organized is up to you, but most groups that I've seen have just come up with a convention that makes sense for their application.
It's generally optimal to package up your files in such a way that you have a small handful of packages which can be included on any given page for optimal caching.
You also might consider dividing your javascript up into segments that are easy to share across the team.
Cal Henderson (of Flickr fame) wrote Serving JavaScript Fast a while back. It covers asset delivery, not organization, but it might answer some of your questions.
Here are the bullet points:
Yes, you ought to concatenate JavaScript files in production to minimize the number of HTTP requests.
BUT you might not want to concatenate into one giant file; you might want to break it into logical pieces and spread the transfer cost over several pages.
gzip compression is good, but you shouldn't serve gzipped assets to IE <= 6, so you might also want to minify/compress your JavaScript.
I'll add a few bullet points of my own:
You ought to come up with a solution that works for both development and production. In development mode, it should pull in extra JavaScript files on demand; in production it should bundle everything ahead of time. Switching from one behavior to the other should be as easy as setting a flag.
Rails 2.0 handles all this through an asset cache; other web app frameworks might offer similar solutions.
As another answer suggests, placing third-party libraries in a lib directory is a good start. You can also divide your own JS files into sub-directories if it makes sense. Ideally, you'll be able to arrange them in such a way that the files in a given sub-directory can be concatenated into one file.
I will have a folder for all javascript, and a sub folder of that for 3rd party/shared libraries, and sub folders for each component of the site to keep everything organized.
For example:
/
+--/javascript/
+-- lib/
+-- admin/
+-- compnent1/
+-- compnent2/
Then run everything through a minifier/obfuscator during the build process.
I'v been using this lately:
http://code.google.com/apis/ajaxlibs/
And then have a "jscripts" folder where I keep my custom code.
In my last project, we had three kinds of JS files, all of them inside a JS folder.
Library code. A bunch of functions used on most all of the pages, so they were put together in one or a few files.
Classes. These had their own files, organized in folders as needed, but not necessarily so.
Ad hoc JS. Code that was specific to that page. These were saved in files that had the same name as the JSP pages they were supposed to run in.
The biggest effort was in having most of the code on the first two kinds, having custom code only know what to call, and when.
This might be a different approach than what you're looking for, but I've been playing around with the idea of JavaScript templates in our blog engine. In a nutshell, you assign a Javascript template to a page id using the database and it will dynamically include and minify all the JavaScript files associated with that template and create a file in a server-side cache with the template id as a file name. When a page is loaded, it calls the template file which first checks if the file exists in the cache and loads it if it does. If it doesn't exist, it creates it on the fly and includes it. I also use the template file to gzip the conglomerate JavaScript file.
The template idea would work well for site-wide JavaScript (like a JavaScript library), but it doesn't cover page-specific JavaScript. However, you can still use the same approach for page specific JavaScript by including a second file that does the same as above.

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